Fluid filtration medium

ABSTRACT

The present application relates to improved filtration of fluids. Particularly, a surfactant-treated zeolite material may be utilized for removing turbid particles from a volume of fluid, such as water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/261,162, filed Nov. 13, 2009.

BACKGROUND

1. Field of the Present Application

The present application relates to improved filtration of fluids.

2. Description of Related Art

Water filtration processes have been developed over the history ofmankind to enhance clarity and to remove impurities from mediums, suchas recreation and potable water. For example, water transported byaqueducts built by Roman engineers for the purposes of filling cityfountains for drinking and bathing were passed through beds of sand toclarify the water.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of an example fluid filtration process accordingto the present disclosure.

DETAILED DESCRIPTION

The present disclosure describes modified, natural surfactant-treatedzeolite products (interchangeably referred to as “zeolite products”);processes for producing the zeolite products, including the bonding ofcation surfactants to zeolite; methods for activating the zeoliteproducts; and use of the zeolite products for enhanced turbidity removalfrom fluids. In some instances, one or more of the zeolite products maybe in a granular form. An advantage of the zeolite products is that thezeolite products provide for improved fluid filtration. For example, insome instances, an example zeolite product may be used in the turbidityreduction of water.

The present disclosure encompasses turbidity-removing zeolites alongwith methods of use and production thereof. One aspect encompasses aturbidity-removing zeolite product including a granulized zeolite and aquantity of cationic surfactant to cover from 20 percent to 100 percentof External Cation Exchange (“ECEC”) sites of the granulized zeolite.

Another aspect encompasses a method of forming a treated granulizedzeolite product that can include applying a cationic surfactant to agranulized zeolite material such that an amount applied to thegranulized zeolite material covers at least 20 percent of the ECEC sitesof the granulized zeolite material.

A further aspect encompasses a method for removing turbid particles froma fluid that can include installing a quantity of surfactant-treatedzeolite in a filter vessel, activating the surfactant-treated zeolite,passing a volume of fluid containing turbid particles through theactivated surfactant-treated zeolite, and removing an amount of theturbid particles from the fluid with the activated, surfactant-treatedzeolite.

The various aspects can include one or more of the following features.The granulized zeolite can include a zeolite having a silica-to-aluminaratio equal to or greater than 2.5. The granulized zeolite can includeat least one of clinoptilolite, mordenite, phillipsite, erionite,chabazite, or faujasite. The granulized zeolite can include at least oneof feldspar, mica, or polymorphs of silica. The granulized zeolite caninclude a cation exchange capacity equal to or greater than 0.5milliequivalents per gram. The granulized zeolite can include a BETsurface area greater than 10 m²/g. The granulized zeolite can include ad₁₀ in the range of 0.3 mm to 0.7 mm and a d₆₀ in the range of 0.6 mm to1.5 mm. The granulized zeolite can include a Uniformity Coefficientequal to or less than 2.2. The granulized zeolite can include a dry,bulk density in the range of 44 to 56 lbs./ft.². The turbidity-removingzeolite product can include a total un-bound moisture content in therange of 12 to 18 percent. The turbidity-removing zeolite product isfree-flowing. The cationic surfactant can include at least one ofpolyamines, quaternary amines, alkylamines, or organo-silane quats.

The various aspects can also include one or more of the followingfeatures. A zeolite product may be formed from of a granulized zeolitematerial. A zeolite material can be crushed, and the crushed zeolitematerial can be sieved with series of sieves, the series of sievesincluding sieves having sieve sizes ranging from a minus 12 mesh (1.7mm) to a plus 50 mesh. (0.3 mm). The crushed zeolite material can have ad₁₀ in the range of 0.3 mm to 0.7 mm and a d₆₀ in the range of 0.6 mm to1.5 mm. The granulized zeolite material can include an un-bound moisturecontent of six percent. Applying a cationic surfactant to a granulizedzeolite material such that an amount applied to the granulized zeolitematerial covers at least 20 percent of the ECEC sites of the granulizedzeolite material can include applying an aqueous solution of cationicsurfactant to the granulized zeolite.

The various aspects can also include one or more of the followingfeatures. Activating the surfactant-treated zeolite can includesaturating the surfactant-treated zeolite in water to cause surfactantcontained within the surfactant-treated zeolite to bond to ECEC sites ofthe zeolite, backwashing the surfactant-treated zeolite, and rinsing thesurfactant-treated zeolite. The surfactant-treated zeolite can include agranulized zeolite formed from at least one of a clinoptilolite,mordenite, phillipsite, erionite, chabazite, or faujasite combined withan amount of cationic surfactant to cover from 20 percent to 100 percentof ECEC sites of the granulized zeolite. The cationic surfactant caninclude at least one of polyamines, quaternary amines, alkylamines, ororgano-silane quats. Removing an amount of the turbid particles from thefluid with the activated surfactant-treated zeolite satisfies criteriadefined ANSI/NSF Standard 50-2009a, Annex B.4.

In the present disclosure, aspects of the zeolite products are discussedwith respect to the filtration of water, although, as indicated above,the scope of the present disclosure is not so limited. Thus, theexamples discussed below are provided merely as examples and are notmeant to limit the applicability of the zeolite products to suchexamples in any way.

In one example implementation, a natural zeolite utilized for producingone or more of the zeolite products may have a silica-to-alumina ratioequal or greater than 2.5. Examples of some of the zeolite minerals inthis group may include clinoptilolite, mordenite, phillipsite, erionite,chabazite, and faujasite. However, many other natural zeolites could beused. In some instances, the zeolite mineral ore may contain greaterthan 50 percent zeolite. In some instances, gangue minerals of clay,evaporates, and calcium carbonate may be avoided as such materials maybe detrimental to the performance of the zeolite product.

In other instances, the zeolite used in the production of the zeoliteproducts may include feldspar, mica, and polymorphs of silica. Suchmaterials may take up space in the zeolite ore but may not bedetrimental to the resulting zeolite product. In some implementations,the natural zeolite may have a total cation exchange capacity equal toor greater than 0.5 milliequivalents per gram and a BET surface area(i.e., a surface area determined using the Brunauer, Emmett and Tellermethod) of greater than 10 square meters per gram (m²/g). In someimplementations, zeolite ore having such properties may be crushed,screened, and, in some instances, dried to an un-bound moisture contentof less than 10 percent The crushed zeolite ore may also be subjected toa screen analysis of approximately minus 12 mesh (1.7 mm) to plus 50mesh (0.3 mm).

Un-bound moisture refers to water associated with zeolite that may beliberated by raising the temperature of zeolite to not more than 212° C.In some implementations, the crushed or granulated zeolite may have ad₁₀ (i.e., a tenth percentile distribution in particle size of thegranular zeolite material) in the range of 0.3 mm to 0.7 mm and a d₆₀(i.e., a 60th percentile distribution in particle size of the granularzeolite material) in the range of 0.6 mm to 1.5 mm. In some instances,the Uniformity Coefficient of the granular zeolite material, a ratio ofd₁₀ to d₆₀, may be less than 2.2. In still other instances, the bulkdensity of the dry, granular zeolite material may be in the range of 44to 56 pounds per cubic foot (lbs./ft.²).

As explained above, implementations of the zeolite products of thepresent disclosure may include one or more of the material propertiesdescribed herein while one or more other properties may vary from thosevalues and/or ranges described. However, the scope of the presentdisclosure is intended to encompass zeolite products having variationsof the property values and/or ranges from those described herein. Thus,the property values and/or ranges described herein are provided merelyas examples and are not intended to limit the scope of the presentdisclosure.

In some instances, a zeolite product according to the present disclosuremay provide backwash performance, for example backwash up to 20 gpm persquare foot, as well as head pressure loss performance, for example headpressure loss of less than 12 psi, that is comparable to media used inmost pressure filtration vessels designed and standardized for the pooland spa industry. Additionally, in some instances, a zeolite productaccording to the present disclosure may also provide suitable flowrates, bed cleaning, and head pressure for gravity filtration systemsutilized in pool, industrial, and municipal applications. In still otherinstances, example zeolite products may be used in gravity-flowfiltration systems favored for use in some potable water, wastewater,pre-treatment streams, irrigation, industrial, or a myriad of otherapplications.

The surface of zeolite granules utilized for the production of thezeolite products may be modified with a chemical of the cationicsurfactant group (referred to interchangeably as “surfactant”). Examplesurfactants may include polyamines, quaternary amines, alkylamines, ororgano-silane quats. The surfactant bonds chemically with the zeoliteforming a surfactant-modified zeolite granule (interchangeably referredto as “surfactant-treated zeolite”) that contains negative ionic chargeswithin the internal crystalline surfaces of the zeolite granule and apositive ionic charge at locations where the surfactant has bonded tothe external crystalline surface of the zeolite granule. Consequently,the modified zeolite provides a crystalline entity with an activeelectrochemical surface that is amphoteric.

It has been shown that the cationic surfactant bonds to particularlocations of the zeolite crystalline structure called the ExternalCation Exchange sites (referred to hereinafter as “ECEC” or “ECECsites”). The surfactants include a carbon chain that is too large toenter the three to 10 angstrom molecular pore spaces within the variouszeolite crystalline structures. The result is a surface-modified zeolite(referred to interchangeably as “modified zeolite”) with the positivecharge moity of the cationic surfactant bonded by cation exchange to thecrystalline surface. At the same time, the zeolite retains a naturalnegative charge at Internal Cation Exchange sites (referred tohereinafter as “ICEC” or “ICEC sites”). The negative charge is availablefor exchange with metal cations that fit within the zeolite'scrystalline lattice.

The surfactant, for example, in the form of an aqueous solution, may beapplied to the granulated zeolite to form a zeolite product. An amountof aqueous solution may be applied to the granulated zeolite so as tointroduce enough surfactant to cover 20 to 100 percent of the ECEC sitesof the zeolite. In some instances, the surfactant may be sprayed orpumped onto the zeolite granules in a mixer to wet the surface of thegranules without saturating the granules. Application of an amount ofsurfactant in excess of an amount to cover 100 percent of the ECEC sitesmay create a double surfactant layer or possibly a micelle layer that isdetrimental to turbidity reduction.

In the context of fluid filtration, a modified zeolite in which 20percent of the ECEC sites is bonded with surfactant may perform as wellor substantially as well as a modified zeolite in which 50 to 100percent of the ECEC sites is bonded with surfactant. Further, cationicsurfactants in which the molecular weight varies from 120 up to over 500may perform similarly with respect to turbidity reduction, independentof whether the carbon chain of the surfactant is C₈ up to or exceedingC₁₆.

According to some implementations, granulated zeolite having six percentun-bound moisture may be metered into a continuous-flow paddle mixer. Asurfactant solution may be pumped onto the granulated zeolite to resultin an eight percent added moisture. In some instances, the aqueoussurfactant solution may contain three and a half percent activeingredient diluted in 96.5 percent water. In still further instances,the granulated zeolite product may exit the paddle mixer with an amountof surfactant to satisfy 50 percent of the ECEC sites. As a result, theoutputted zeolite product may contain a total un-bound water of 14percent.

Because zeolite granules are micro-porous and hydrophilic, many, if notmost, natural zeolite mineral ores can hold up to, and in some casesexceed, 18 percent un-bound moisture while remaining free-flowing.Consequently, granulated zeolite to which enough surfactant has beenadded to satisfy up to 100 percent of the ECEC sites may remain a volumeof free-flowing granules that may be processed accordingly. As such, thetreated zeolite granules described herein may be processed andtransported in manners similar to other dry bulk materials. Further,because the surfactant-treated zeolite retains a free-flowing condition,additional processing, such as processing to dry out the zeolitematerial is not required, leading to processing time and cost savings.

Decreasing the un-bound moisture content in the surfactant-treatedzeolite may cause the zeolite granules to become difficult to wet whenintroduced into a filtration vessel. For example, the surfactant on adry zeolite granule forms a hydrophobic surface that is difficult to wetwhen placed into a filtration vessel. As such, according to someimplementations, moisture in the surfactant-treated zeolite granules maynot be removed. In some instances, surfactant-treated zeolite granuleshaving a moisture content of between 12 and 18 percent may be easilywetted when introduced into a filtration vessel.

As explained above, the granulated zeolite is free-flowing and, thus,may be handled in ways similar to other bulk materials. As such, oncethe surfactant is applied (as well as at other times during theprocessing of the zeolite), the granulated zeolite may be handled bystandard package equipment for dry, free-flow products and stored inbins, bagged, or otherwise packaged. In some instances, thesurfactant-treated zeolite granules may be packaged in paper or polyfilm. In this manner, the surfactant-treated zeolite granules are highlystable and may enjoy a shelf life in excess of several years. Activationfor complete ion-exchange of the cationic surfactant onto the zeolitegranules may be completed at a later stage.

Activation may be completed when the pre-sorbed zeolite granules, i.e.,surfactant-treated zeolite granules in which the surfactant has not beenbonded to the zeolite particles, are placed into a vessel and saturatedwith water. For example, the pre-sorbed zeolite granules may beactivated by introducing the zeolite granules into a filter vessel foruse in a desired application and saturating the zeolite granules withwater. Saturation of the zeolite granules causes the cationic surfactantto re-solubilize and come in contact with the crystalline surfaces ofthe zeolite in the aqueous phase. Consequently, the ion exchange betweenthe zeolite and the surfactant occurs.

In excess of 80 percent of the chemical bonding of the surfactant to thezeolite is typically complete within 20 minutes at ambient temperature.Once activation is complete or substantially complete, the modifiedzeolite may be used as a filtration medium. In some instances,activation may be allowed to proceed for 24 hours before use, while, inother instances, activation may be allowed to proceed for 24 hours priorto use of the filtration medium.

In some instances, “backwash” procedures and “rinse to waste” cycles maybe performed once the media has been activated or substantiallyactivated and prior to using the activated zeolite filtration medium infiltration mode. However, in other instances, backwashing and/or “rinseto waste” cycling may not be required or desired prior to utilizing theactivated zeolite filtration medium in filtration mode. The backwashingand “rinse to waste” cycles may be utilized to wash out any excess,un-bonded surfactant as well as detritus that would interfere with thefiltration process. In some implementations, a backwash may include atleast three bed volumes of flush water, while a “rinse to waste” cyclemay include at least one bed volume of water.

FIG. 1 shows a flowchart of an example production process 10 for asurfactant-treated zeolite. At 20, a zeolite material, such as one ormore of the zeolite materials described above, may be extracted from theearth. At 30, the extracted zeolite material may be subjected to one ormore operations or processes granulize the zeolite material. Forexample, the zeolite material may be subjected to crushing and/orscreening. As explained above, in some instances, the zeolite may becrushed and subjected to a minus 12 mesh (1.7 mm) to plus 50 mesh (0.3mm) screening analysis. In other implementations, a screening analysismay encompass a broader or narrower range. For example, an applicationof the granular zeolite may define one or more of the crushing orscreening operations to which the zeolite material is subjected.Further, in some implementations, a granular zeolite having a d₁₀ withinthe range of 0.3 mm to 0.7 mm and a d₆₀ within the range of 0.6 mm to1.5 mm.

In some instances, the zeolite material may be subjected to one or moredrying operations. For example, a desired un-bound moisture content ofsix to ten percent water may be desired. The initial moisture content ofthe zeolite material may determine whether or not one or more dryingoperations are required.

At 40, the granular zeolite material may be introduced into a mixingapparatus along with an amount of surfactant, such as one or more of thesurfactants described above. Dispensation of one or more of the granularzeolite or surfactant may be metered. For example, one or more of thegranular zeolite or surfactant may be metered such that asurfactant-treated granular zeolite material in which 20 to 100 percentof the zeolite's ECEC sites are bonded with the surfactant results. At50, the surfactant may be formed into an aqueous solution of a desiredconcentration. For example, in some instances, the aqueous solution maybe 3.5 percent surfactant and 96.5 percent water. However, such solutionis merely an example. Thus, other surfactant solution concentrations maybe used.

In some instances, the surfactant and the granular zeolite may becombined such that the un-bound moisture content does not exceed 18percent. In other instances, the un-bound moisture content may be loweror higher than 18 percent. In some instances, a fluid, in addition tothe surfactant solution, may be introduced into the mix to control theun-bound moisture content, while, in other implementations, additionalfluids may not be used. Further, controlling the un-bound moisturecontent so as not to exceed 18 percent allows the treated zeolitegranules to remain free-flowing, facilitating the ease of subsequentprocessing of the material.

The surfactant-treated zeolite material may be transferred to apackaging process at 60. The treated zeolite material may be packaged inany desired manner. For example, in some instances, the treated zeolitemay be packaged into paper or poly film containers. The containers maybe of any desired size. In other instances, packaging may be avoided andthe material may be distributed, for example, in bulk via rail cars,trucks, etc.

At 70, the surfactant-treated zeolite material may be utilized forfiltration of fluids. For example, the treated zeolite material may beused in the filtration of water sources. Particularly, the treatedzeolite may be used to remove turbid particles from a water source. Insome instances, feature 70 may represent a filtration vessel 80 having abed of the surfactant-treated zeolite 90 with a water layer 100 abovethe zeolite bed 90.

Further, in some instances, the treated zeolite material may beactivated at 70. For example, during activation, the surfactant-treatedzeolite may be soaked in an excess of water (e.g., saturated) in thefiltration vessel 80 for a desired period of time. In someimplementations, the treated zeolite material may be soaked for 20minutes at ambient temperature to complete activation. In otherexamples, activation may be permitted to occur for longer or shorterperiods. For example, the treated zeolite may be allowed to soak inexcess water for 24 hours or more prior to use. In other examples, thetreated zeolite material may be soaked for between 20 minutes and 24hours prior to use.

The activated surfactant-treated zeolite may be backwashed prior to use.Backwashing may be performed, for example, to remove excess surfactantand/or detritus. One or more cycles of “rinse to waste” may also beperformed prior to use of the surfactant-treated zeolite in filtering afluid source.

While the above description provides examples with regard to theprocessing and/or production of the surfactant-treated zeolite, such areonly examples and are not meant to limit or otherwise define the scopeof the present disclosure. Consequently, production and/or use of thesurfactant-treated zeolite may vary from those provided herein whileremaining within the scope of the present disclosure.

Several examples involving the use of the modified granular zeolitematerial are described below.

Example No. 1

In Example No. 1, several filtration media were tested in a 12 inch-longpolycarbonate column having a 2.5-inch inner diameter (“ID”)(hereinafter referred to as “column”). The column was prepared withO-ring-fitted stoppers on both ends. A pump having a ball valve controlwas plumbed to pull water at various flow rates from a 20 literreservoir with down-flow, through the column, and back to the reservoir.The filtration media were pre-washed or prepared and placed in thecolumn such that the filtration medium formed a bed height of sixinches. A 50 mesh stainless steel screen was disposed at a lower end ofthe filtration medium. A perforated plastic disc was placed on an upperend of the filtration medium, and a three-inch head of water wasmaintained above the upper end of the filtration medium to preventscouring from the high-volume water flow entering the column.

Flow rate of the water was determined by measuring the rate at which thewater was discharged from the column. Flow rate was adjusted with anin-line ball valve. Each filtration medium was backwashed after beingplaced into the column with about a 30 percent bed lift until clearwater resulted. The bed was further cleaned by a brief down-flow rinse.For each filtration medium, the column was then capped and fitted withan inlet and outlet hose. Water flow rate was regulated between 15 and20 gpm per foot squared of media surface area (gpm/ft²).

The 20 liter reservoir was filled with tap water and adjusted to about50 NTU (Nephelometric Turbidity Unit) with U.S. Silica ground silica(Sil-co-sil #106), produced by U.S. Silica Company of Berkeley Springs,W. Va., to make up the challenge water. A LaMotte Model 2020turbidimeter, produced by LaMotte Company of 802 Washington Avenue,Chestertown, Md., was used for all of the turbidity testing. Circulatingwater in the clean bed was measured at less than 2 NTU in all trialsbefore the challenge water was introduced to the columns. Operationalprocedures and calculations follow NSF/ANSI Standard 50-2009a, part B5.

TABLE 1 Experimental Results of Example 1. End NTU ECEC after PercentCoverage Starting Five (5) Turbidity Media Treatment Percent NTUTurnovers Reduction Silica Sand None — 60 25 58 Zeolite #1 None — 50 1374 Zeolite #2 None — 54 24 55 Zeolite #3 None — 53 30 43 Treated #1HDTMA 100 49 1.1 98 Treated #2 HDTMA  50 52 2.1 96 Treated #3 DADMA 10060 8.0 86 Treated #4 DADMA 100 50 4.0 92

With respect to Table 1, above, Silica Sand is filter sand obtained fromLeslie's Swimming Pool Supply of 2740 Wyoming Blvd NE, Albuquerque, N.Mex. 87111. Zeolite #1 is Clinoptilolite produced by St. Cloud MiningCo., of Winston Millsite Winston, N. Mex. 87943. Zeolite #2 isClinoptilolite produced by Zeotech Corporation of 115 West 7th Street,Suite 1400, Fort Worth, Tex. 76102. Zeolite #3 is Clinoptiloliteproduced by Bear River Zeolite Co., of 4323 East Glendale Road, Preston,Id. 83263. Treated #1 is a surfactant-treated zeolite formed fromHexadecyltrimethyl ammonium chloride (interchangeably referred to as“HDTMA”) on Zeolite #1 soaked for 3 hours. Treated #2 is asurfactant-treated zeolite formed from Hexadecyltrimethyl ammoniumchloride on Zeolite #1 soaked for 30 minutes. Treated #3 is asurfactant-treated zeolite formed from Dimethyldialyl ammonium chloride(interchangeably referred to as “DADMA”) on Zeolite #1 soaked for 40minutes. Treated #4 is a surfactant-treated zeolite formed fromDimethyldialyl ammonium chloride on Zeolite #1 soaked for 8 minutes.

The turbidity reduction for Silica Sand and three untreated,commercially available zeolites (Zeolites #1, #2, and #3, respectively)commonly used in water filtration systems varied from 43 to 74 percentremoval after five turnovers. It is noted that a turnover is the time inwhich the water volume in the reservoir, flowing at a given flow rate,would have completely passed through the filtration medium bed. Thus,five turnovers is the amount of time, at a given flow rate, the amountof water in the reservoir would have passed through the filtrationmedium bed five times. Testing in columns and in commercial applicationsover the last several years suggest that the removal rates determinedand listed in Table 1 are typical removal rates for these products,i.e., the Silica Sand and Zeolites #1, #2, and #3.

On the other hand, the results of turbidity reduction for all of thesurfactant-treated zeolites show a marked improvement. HDTMA-treatedzeolites or DADMA-treated zeolites had a turbidity reduction of 86 to 98percent after five turnovers. Results also indicate that a DADMA-treatedzeolite in which the DADMA was allowed to soak into the zeolite granulesfor eight minutes performed as well as a DADMA-treated zeolite in whichthe DADMA was allowed to soak into the zeolite granules for 40 minutes.Similarly, results indicated that HDTMA-treated zeolite in which theHDTMA was allowed to soak into the zeolite granules for 30 minutesperformed as well as a HDTMA-treated zeolite in which the HDTMA wasallowed to soak into the zeolite granules for three hours.

Example No. 2

In Example No. 2, a series of four consecutive filtration runs andbackwashes were made with a surfactant-treated zeolite medium todetermine attenuation of turbidity removal over time and use. Zeolite #1was sorbed at a level of 25 percent of the ECEC with an organo-silanecompound. Dry zeolite granules were sprayed with a 2.5 percent solutionof the organo-silane compound (interchangeably referred to as “silanesolution”). Particularly, the organo-silane compound used was Zycrobialproduced by Zydex Industries of 25-A Gandhi Oil Mill Compound, Gorwa,Vadodara-390016, Gujarat, India. Six hundred cubic centimeters of filtermedia were sprayed with 60 milliliters of the silane solution. Thetreated zeolite that resulted was free-flowing.

A twelve-inch column similar to the one described in Example No. 1,above, was loaded with the surfactant-treated Zeolite #1 and soaked withenough tap water to cover the media for 30 minutes. The column was thenbackwashed and rinsed. Challenge water containing 60 NTU of Sil-co-sil106 was flowed through the column at a rate of 20 gpm per foot squaredof media surface area.

Turbidity measurements were taken at the end of each turnover on a 20liter reservoir for five turnovers and results were recorded. At the endof the five turnovers, the column was backwashed and rinsed prior toperforming a subsequent filtration test with new challenge water. Thisprocedure was repeated twice using. Sil-co-sil 106 as the watercontaminant and twice using ISO 12103-1 A3 Medium Test Dust as the watercontaminate. The results are shown below in Table 2.

TABLE 2 Experimental Results of Example 2. NTU at NTU at Percent RunInitial First Fifth Removal after No. Contaminant NTU Turnover TurnoverFifth Turnover 1 Sil-co-sil 106 60 5.0 1.0 98 2 Sil-co-sil 106 55 4.50.3 99 3 A3 Medium Test 60 5.3 1.0 98 Dust 4 A3 Medium Test 95 22 2.6 97Dust

The results demonstrate continued efficacy for turbidity reduction ofthe surfactant-treated zeolite through four column runs of fiveturnovers, each run being followed by rigorous backwash. The results ofRun No. 1 show that the surfactant-treated zeolite removed 98.3 percentof turbidity from a 60 NTU challenge water after five turnovers, whilethe results of Run No. 4 show that the surfactant-treated zeoliteremoved 97.3 percent of the turbidity from a 95 NTU challenge water onthe fifth turnover. Based on the test results, it is believed that theorgano-silane is bonded to the zeolite and remains effective afterconsiderable “break-in” use.

Example No. 3

Example No. 3 addresses whether salinity content of a challenge wateraffects the turbidity reduction properties of a surfactant-modifiedzeolite. Many modern swimming pools as well as some industrialapplications require filtration of saline or brackish water. Salineswimming pools generally regulate salt content at 1,500 to 3,000 ppmsodium chloride (“NaCl”). A concern is that a high sodium ionconcentration in contact with the surfactant-modified zeolite maydegrade the zeolite by exchange of and/or displacement of the cationicsurfactant bonded to the zeolite crystalline surface at the ECEC sitesby the sodium ions.

In Example No. 3, a column was set up in a manner similar to thatdescribed above in Example No. 1 with Zeolite #1 sorbed with DADMA so asto cover 20 percent of the ECEC sites. A recirculating body of water wasprepared containing 3,000 ppm of NaCl. Clear recirculating water had aturbidity level of 0.4 NTU. Sil-co-sil 106 was utilized to form achallenge water having turbidity level of 45 NTU. Results of Example No.3 are shown in Table 3.

TABLE 3 Experimental Results of Example No. 3. Turbidity RemovalTurnover NTU Percentage 1 21 53 2 5.5 88 3 2.8 94 4 1.8 96 5 WaterSpilled —

The results demonstrate that the surfactant-modified zeolite produces asuperior turbidity reduction despite a high salinity content of thechallenge water. The anomalous reading in turnover No. 1 may have beenfrom a “bumping” of the column resulting in an upset. Data from turnover5 was lost due to a spillage. Nevertheless, the data associated withturnovers 2 through 4 are consistent with having the surfactant fullyfunctional and remaining on the zeolite media in spite of the highsodium content of the challenge water.

Example No. 4

Example No. 4 tested the cleanability of a surfactant-modified zeolitefilter medium using a test procedure defined in ANSI/NSF Standard50-2009a, Annex B.4. A 24-inch diameter, high-rate sand filter vesselwas used. One hundred fifty pounds of Zeolite #2 was sorbed with enoughDADMA to cover 50% of the ECEC sites. The surfactant-modified zeoliteand loaded into the filter vessel. After backwash and rinse, clean waterwas run through the filter, and an initial static head loss of 9.2 psiat a flow of 20 gpm/ft² was measured across the filter vessel.

A mixture of 1.89 lbs. of ball clay, 0.03 lbs. of baby oil, and 1.89lbs. of diatomaceous earth was mixed into a slurry. The slurry was addedto the re-circulating water until the pressure across the filter vesselincreased to 24.05 psi. The filtration mode was stopped and backwashmode was initiated.

Backwash continued for five minutes at 63 gpm (20 gpm/ft²) followed by afilter rinse of one minute. The vessel was then turned back on tofiltration mode. The head loss measured across the filter vessel was 9.1psi. The results show slightly less head loss pressure than the startingvalue of 9.2 psi. Consequently, the results of this example demonstrateexcellent cleanability of the surfactant-modified zeolite filtrationmedium.

Example No. 5

In Example No. 5, a turbidity reduction test was run on twosurfactant-modified zeolite media in accordance with the procedureoutlined in ANSI/NSF Standard 50-2009a, Annex B. Tests were performed on150 lbs. of media placed into a 24-inch diameter, Sta-Rite pressurefilter. A 1,000 gallon test tank was used with a cross-sectionalflow-rate of 20 gpm/ft² of media. The challenge water was prepared byadding ground silica (Sil-co-sil 106) until the challenge water reacheda turbidity of 45±10 NTU. A sample of the challenge water was measuredfor turbidity (NTU) at the end of each reservoir turnover. Turnover ofthe reservoir at a total flow rate of 63 gpm was 9 minutes, 39 seconds.

Two different filtration media were tested, a surfactant-modifiedZeolite #2 and a surfactant-modified Zeolite #1. Results are presentedbelow in Tables 4 and 5, respectively. For the surfactant-modifiedZeolite #2, the water used to form the challenge water had a turbiditylevel of 0.88 NTU, while the challenge water had a turbidity level of49.3 NTU. For the surfactant-modified Zeolite #1, the water used to formthe challenge water had a turbidity of 0.53, while the challenge waterhad a turbidity level of 40.8 NTU.

TABLE 4 Experimental Results for Surfactant-Modified Zeolite #2 with 50%ECEC DADMA. Turnover Effluent Turbidity Percent Removal 1 12.00 75.7 27.02 85.8 3 4.46 90.9 4 2.51 94.9 5 1.39 97.2 Notes: Initial Turbidity -0.88 NTU; Challenge Water Turbidity - 49.3 NTU

TABLE 5 Experimental Results for Surfactant-Modified Zeolite #1 with 50%ECEC DADMA. Turnover Effluent Turbidity Percent Removal 1 4.36 89.3 20.59 98.5 3 0.44 98.9 4 0.34 99.2 5 0.43 98.9 Notes: Initial Turbidity -0.53 NTU; Challenge Water Turbidity - 40.8 NTU

For the test defined by ANSI/NSF Standard 50-2009a, Annex B, the NSFrequires at least a 70 percent turbidity reduction by the fifth turnoverin order to pass the test. Both filtration media surpassed a 70 percentturbidity reduction by the first turnover. Accordingly, thesurfactant-modified zeolites demonstrate a superior ability for reducingturbidity.

Example No. 6

Both significant reduction in turbidity particles (“TSS”) as well as adetermination of the “fineness” of filtration are important aspects influid filtration, particularly in the filtration of potable watersupplies. The “fineness” of filtration is sometimes referred to as“micron reduction” or “nominal particle reduction”. These terms relateto the smallest particle size effectively removed by a given filtermedium.

To obtain an approximation of relative particle removal from filteredwater, several columns were prepared with sand and various zeolitemedia. The media were placed in 2.5-inch ID polycarbonate columns. Thebed depth for the filtration media was eight inches. The media werebackwashed, rinsed, and flooded with tap water containing 30 NTU of ISO12103-1 A3 Medium Test Dust at a flow rate of 15 gpm/ft². The influent,i.e., the challenge water containing the test dust prior to being passedthrough the filtration media, included particles from 0.7 to 70 microns.The 85th percentile of particles measured 22 microns. A particle countof the control water reservoir was taken from samples of the challengewater at the beginning and end of the trial, as shown in Table 6.

The challenge water was pumped into the columns containing the mediawith approximately three inches of water above the upper end of themedia bed. For the filtration media used for testing, an eight-inch beddepth within the columns contains approximately 350 ml of open porespace, also referred to as pore volume. Five liters of challenge water(14 pore volumes) were passed through each column at a rate of 15gpm/ft². Immediately after the passing five liters of challenge waterthrough the columns, a 250 ml aliquot sample of effluent, i.e.,challenge water after having passed through the filtration media, wastaken and analyzed for particles. The particle content data are reportedin Table 6, below.

Table 6 contains particle size data for various samples, showing thereduction in particle sizes of particles contained in the challengewater before and after passage through the filtration media.Particularly, Table 6 includes sample data for the 50th percentile and85th percentile particle sizes. The percentile values were obtained froma particle size distribution curve plotted on semi-log paper for each ofthe samples. The analyses were run on a Microtrac X100, produced byMicrotrac, Inc., of 44 Hokes Mill Road, York, Pa. 17404, with a run timeof 30 seconds, done in triplicate.

TABLE 6 Particle Size Reduction in Microns. Influent Particle ParticleSize Effluent Sample Turbidity Size @ Size @ Range Of Turbidity No.Media NTU 50% 85% Particles NTU Control A3 Med Test Dust 30 9.0 220.7-70 NA 9909-1 Silica Sand, #20 30 8.0 15 0.7-20 30 9909-2 Zeolite #330 6.0 12 0.7-30 25 9909-3 Zeolite #1 30 8.0 12 0.7-30 27 9909-4 Zeolite#2 30 7.0 15 0.7-30 — 9909-11 Zeolite #1 with 30 2.5 3.5  0.7-5.0   2.5DADMA 9909-6 Zeolite #2 with 30 2.5 3.0  0.7-5.0 10 DADMA Control A3 MedTest Dust 30 8.0 18 0.7-70 NA

The tests represent severe conditions in that the filtration media arelimited to an eight-inch bed depth, the challenge water flow rate was 15gpm/ft², and the samples were collected after only 5 liters, or 14 porevolumes, of challenge water had been passed through the columns. Theseresults may not reflect data that would be collected through strictANSI/NSF 42 protocol. However, the test results for each filtrationmedium can be compared relative to each other.

Challenge water with A3 Medium Test Dust has an 85th percentile particlesize of 22 microns. The results for silica sand, Zeolite #1, Zeolite #2,and Zeolite #3 were similar to each other with the 50th percentile from6 to 8 microns and 85th percentile from 12 to 15 microns.Surfactant-treated Zeolite #1 with DADMA and Zeolite #2 with DADMAremoved turbidity effectively, as demonstrated in prior examples. TheECEC coverage of the treated zeolites was approximately 50 percent.However the particle analysis of the remaining turbid particles showsparticle size reduction to the range of 2.5 to 3.5 microns. This isexcellent for a granular media and far superior to the untreated samplesof Zeolite #1 and Zeolite #2.

Example No. 7

Example No. 7 addressed the effect of chlorine concentrations on thesurfactant-modified zeolites. Water in pools, spas, and waterattractions routinely require “chlorine shock” or similar severedisinfectant treatment in order to reduce the level of pathogens. Theoxidation potential of a typical chlorine shock of 20 to 30 milligramsper liter of “free-chlorine” is a concern for the longevity of a cationsurface-modified zeolite medium.

A test was performed to determine any degradation of thesurfactant-modified zeolite filtration media caused by a 35 milligramper liter chlorine shock. A sample of Zeolite #1 was prepared with DADMAat 80 percent ECEC loading. A filtration column was prepared in a mannersimilar to that described above in Example No. 1. Results are providedin Table 7.

TABLE 7 Experimental Results of Example No. 7. NTU after NTU afterPercentage Run Chlorine Initial First Fifth Removal after No. Level inPPM NTU Turnover Turnover Fifth Turnover 1 2 81 5.5 3.8 95.3 2 35 67.338.2 23.6 64.9 3 2 86 3.0 0.8 99.1 4 2 80 7.8 3.1 96.1 5 2 85 9.7 3.995.4

The results of Table 7 show removal of ISO 12103-1 A3 Medium Test Dustof greater than 90 percent at five turnovers. The water flow for allfive runs was 12 gpm/ft.². Run No. 1 was performed to establish baselineperformance. In Run No. 2, milligrams per liter of free chlorine in theform of sodium hypochlorite was added to the reservoir. The highchlorine level considerably reduced the turbidity reduction.Particularly, the turbidity reduction obtained from thesurfactant-modified zeolite decreased from the 90 percent and greaterturbidity reduction observed in previous tests to about a 65 percentreduction. Three subsequent runs were made with the same media afterbackwash and rinse. Run No. 3, immediately following the high chlorineshock, gave the best results for turbidity removal—a 99.1 percentturbidity reduction. Consequently, it is believed that the bondedsurfactant, the DADMA in this particular example, was not removed,degraded, or oxidized by the high-chlorine level. Rather, theperformance of the surfactant-modified zeolite was improved. Run Nos. 4and 5 continue to show the DADMA sorbed onto the zeolite being effectivein subsequent filtration runs after backwash.

Although the present disclosure has been described with severalimplementations, various changes and modifications may be suggested toone skilled in the art. It is intended that the present disclosureencompass such changes and modifications as fall within the scope of theappended claims and their equivalence.

1. A turbidity-removing zeolite product, comprising: a granulizedzeolite; and a quantity of cationic surfactant to cover from about 20percent to about 100 percent of External Cation Exchange (“ECEC”) sitesof the granulized zeolite.
 2. The turbidity-removing zeolite product ofclaim 1, wherein the granulized zeolite comprises: a zeolite thatincludes a silica-to-alumina ratio equal to or greater than about 2.5.3. The turbidity-removing zeolite product of claim 1, wherein thegranulized zeolite comprises: at least one of clinoptilolite, mordenite,phillipsite, erionite, chabazite, or faujasite.
 4. Theturbidity-removing zeolite product of claim 1, wherein the granulizedzeolite comprises: a cation exchange capacity equal to or greater thanabout 0.5 milliequivalents per gram.
 5. The turbidity-removing zeoliteproduct of claim 1, wherein the granulized zeolite comprises: a BETsurface area greater than about 10 m²/g.
 6. The turbidity-removingzeolite product of claim 1, wherein the granulized zeolite comprises: ad₁₀ in the range of about 0.3 mm to about 0.7 mm and a d₆₀ in the rangeof about 0.6 mm to about 1.5 mm.
 7. The turbidity-removing zeoliteproduct of claim 6, wherein the granulized zeolite comprises: aUniformity Coefficient equal to or less than about 2.2.
 8. Theturbidity-removing zeolite product of claim 1, wherein the granulizedzeolite comprises: a dry, bulk density in the range of about 44 lbs/ft²to 56 lbs/ft².
 9. The turbidity-removing zeolite product of claim 1,wherein the turbidity-removing zeolite product comprises a totalun-bound moisture content in the range of 12 to 18 percent.
 10. Theturbidity-removing zeolite product of claim 1, wherein theturbidity-removing zeolite product is free-flowing.
 11. Theturbidity-removing zeolite product of claim 1, wherein the cationicsurfactant comprises: at least one of polyamines, quaternary amines,alkylamines, or organo-silane quats.